Polar relay



Marchl6, 1943. LI'TTLE HAL 2,314,228

POLAR RELAY Filed Sept. 13, 1941 Rec.

* INVENTCSRS RJLitt Is and TJJudge BY THEIR ATTOR'NEY 2 Sheets-Sheet lMarch 1 1943.

R. J. LITTLE ET AL POLAR RELAY Filed Sept; 13, 1941 2 Sheets-Sheet 2INVENTORS QJL'IW: and TJJud ge BY MWMK,

THEIR ATTORNEY Patented Mar. 16, 1943 UNITED STATES PATENT OFFICE POLARRELAY Application September 13, 1941, Serial No. 410,724

9 Claims. (Cl. 175-320) This invention relates in general to relays foruse in railway signalling systems, and the like, and has more particularreference to an improved slow release quick pick-up retained neutralpolar type of relay.

In certain situations, as will appear more clear from the following, itis desirable in the case of neutral polar relays, to provide a devicewhich is quick to pick up upon being energized, but which is slow torelease when deenergized, and which retains its neutral armature inpicked up position while energization of the relay is being pole changedand during any short deenergization. This is particularly the case witha relay employed to respond to current which is so coded as to comprisea series of short current impulses separated by short blank, or offcurrent periods, and, in which the current impulses are of one polarityfor some, and of the other polarity during another period of time, andin which the rate of coding may be relatively fast or slow.

In cases as referred to just above, a relay which is slow to release soas to bridge over the blank periods of code, may not be quick enough topick up to respond to the short spaced current impulses. Furthermore, ifthe relay be quick enough in picking up to respond to the currentimpulses, it may not be slow releasing enough to enable it to hold upover the oil periods of code. Thus, it is desirable to provide a relaywhich is quick to respond to energy and to reach its picked up position,which is slow to release and hence retains its picked up conditionduring the off periods of code, and which is provided with suitableretaining means so that it can retain its neutral armature in picked upposition during pole changing of its energization.

-With the above and other objects in view, it is proposed in accordancewith the present invention to provide a relay having a main winding anda retaining winding and soassociate these windings with slow releasemeans and a rectifier as to accomplish the above purposes, and toaccomplish all this in an economical and efiicient manner.

Further objects, purposes and characteristic features of the presentinvention will appear as the description progresses, reference beingmade to the accompanying drawings, showing solely by way of example andin no manner whatsoever in a limiting sense, one form which theinvention can assume. In the-drawings:

Fig. l is a sectional elevation of a commercialized form of relayembodying one form of this invention.

Fig. 2 is a schematic view of a relay embodying the present invention.

Fig. 3 is a schematic view of a track signalling system in which arelay, constructed in accordance with this invention, is of particularvalue.

Referring now to the drawings and first to Fig. 1, there is here shown arelay having a usual top plate I, and an enclosing casing 2 connected tothe plate as by bolt means 3. This relay, in general, is constructed asdisclosed in the O. S. Field Patent 1,749,331, granted March 4, 1930,and in the J. E. Willing Patent 1,969,055, granted August 7, ,1934.Thus, a detailed description of the construction other than that whichis particularly applicable to the present invention should be quiteunnecessary.

The construction of the relay and the circuit arrangement can be easilyunderstood from a consideration of Fig. 2, in which figure the partscorresponding to those of Fig. 1, bear like reference characters.

In Fig. 2 is shown a pair of'main cores MC interconnected by a backstrap 4, and a pair of retaining cores RC interconnected by a back strap5. On the main cores are main windings MW, and on one of the retainingcores is a retaining winding RW. The other retaining core issuppliedwith choke means in the form of an elongated copper cylinder S, sleevedon the core, and furnishing a low resistance short-circuited winding onthis core. In some cases copper sleeve may be omitted by using fullwinding. The retaining winding is connected by wires 6 and 1 to theoutput side of a full-wave rectifier Rec., the input side of therectifier being connected by means of Wires 8 and 9 across the majorportion of the main winding MW. A few turns of. the main winding, ateach end of the same, such as It] and H, are positioned ahead of thewires 8 and 9 so as to supply an inductive winding or choke at each sideof the rectifier for protection against lightning, and the like.

The; main winding is shown as connected to a source ,of energy such as abattery l2 through a pole changing switch I3'--l4 controlled by anyusual means as a hand lever 15,. whereby the lever can be operated toeither deenergize the relay or to energize it with one, or the other,polarity of current.

A movable neutral armature NA is shown as pivoted at l6 and positionedto be attracted to the pole shoes I1 and H! of the main cores and to thepole shoes I 9 and 20 of the retainingcores, when the respectivewindings are energized. This neutral armature carries'a contact finger2| mov able by gravity to make up a back point 22, and movable to makeup a front point 23 under energized conditions.

A polar armature PA is provided on a pivot 24 and carries a contactfinger 25 which is electrically controlled by the main cores andwindings to assume either a normal or reverse energized position againsta normal contact point 26 or a reverse contact point 27, and to retainits energized position until energized to a different position.

The relay constructed as described above thus has both a neutral and apolar armature, and

upon energization with either polarity of current the neutral armatureis picked up, and the, polar armature, dependent upon polarity ofenergization, moves to either its normal or reverse position. Upondeenergization of the relay, the decay. of flux in the main coresinduces a voltage in the.

main windings and likewise the decay of flux in the retaining coresinduces a voltage in the retaining winding, which voltages are in thesame direction in a series circuit including these windings, andtherectifier Rec. This circuit can be traced to include wire 8, rectifierRec, Wire 6, winding RW, wire I, rectifier Rec, wire 9, the majorportion of the main winding MW, and wire 8., This circuit allows aconsiderable current to flow and thus opposes the decay of flux in boththe main windings and theretaining winding. Furthermore, the decay of.flux in the retaining cores induces a voltage in sleeve S to cause acurrent to, flow therein which strongly opposes the decay of flux in.these cores.

operation of the relay.

. Regardless of slow, release means, suchas described above, if thepolarity of energization is changed, the flux in the cores mustpassthrough zero, andhence theneutral armature will release,

unless means is provided to prevent this. By employingthe rectifier Rec,itcan be seen that the direction of current flow. in the retaining.windinglis always in the same directionregardless of. the direction ofit energization from the source. l2.- Accordingly, the relay willeffectually. hold. up duringthe; blank or off periodsof currentoccurring in a code and its neutral armature will-be retained inattracted position when thecode is. changed from a plurality of currentimpulses .ofone polarity to a plurality of current impulses of the otherpolarity. Since the slow release means. in the formof the sleeve S isplaced on the core structure of. the. retaining means it will notadversely affect the operation of the main windings in rapidly. pickingup the armatures. Thus, with this arrangement of parts the .slow releaseeffect is produced not only by th rectifier and by the sleeve S butbythe connection between the main winding and the retaining winding in aseries circuit with each other.

Referring now to .Fig. 3, there is here shown a fragmentary portion of arailway. wayside signal system of the absolute-permissive-block type,such, for example, as disclosed in the Judge application, Ser. No.378,961, filed February 14, 1941; forfCoded track circuit signallingsystems. For the purpose of disclosing the present invention, it shouldbe necessary to merely summarize the operation of this system whereby topoint out the advantages accruing from the employment in such systems ofrelays constructed in accordance with the present invention.

A.stretch of single track constituted by track rails 39 is, shown,signalled. for east boundiand All this results in producing a very slowreleasing:

west bound travel, by means of signals Sl2, SH, SIB, and signals Sl9, SHand Sl3, respectively.

In systems of this type, at one end of each block, such as the blockhaving the entering signals SM and SH, there is a code transmitter CTwhich operates to intermittently place energy across the track rails atone end of the block at a desired rate, as for example, 75 times perminute. At the other endof the block a track relay TR responds to thecode and follows it so as to pick up and release for each on and offperiod of current.

This track relay, through its front point, controls a front repeaterrelay FP while through its back point and in conjunction with the relay'FP, controls a front-back repeater FBP. Thus, upon the coder failing tofunction to intermittently energize the track circuit and also. uponoccupancy, the front-back repeater relayreleases to indicate occupancyand control the signals.

The'code transmitter and the trackrelay operate in synchronismwherebywhen both relays are inattracted position, the'signal. control relay. I 4HD is'energized whilegwhen both areine retracted position theignal controlxrelay ITHD is. energized.

These HD relays can, to. advantage, be. con. structed. in. accordancewith the. present invention, and asidescribed above. rate code inforce,v they are energized intermittently '75 times per minute; and;aredeenergized the. same number of timesper. minute. Accordingly, aslowrelease relay, which, is not fast. to pick up. might: easilyfail: to;pickaupin response. to the on periods. of.code,..while on theotherhandya fast: pick-up. relay, which is not slow to release, might. failto. h'oldfup' during the "oif periods of. code. The retaining winding onthe retaining core can be adjusted in any desirableway tomake the relayvas slow releasing 'as desired without interfering with.v the, quick:pick-up characteristics. of. the relay and furthermore, the; inductiveeffect of the main winding on the. rectifier fed retaining coil makesthe relay additionally slow torelease'.

The slow release means, shown: in the form of the sleeve. S,.is butoneernbodiment ofthe invention and this. sleeve can: be replaced by alonger or ashorter one, or by a winding of heavyv Wire withisuitableadjustment taps.

The signals: such. as: SM, employed. inv this system are, of; theSAtype, as. forv example, those described in; the; Judge. application Ser.No; $2 8,961, referred: to above. Thistype of signal. ordinarily.requires a: home Ldistant: or HD relay; to control, it,v andirequiresiaseparate yellowgreen repeater relay to; repeatthezyellowsand' the green"indicationssofithe signakandretain its picked up'position. duringthe-.movementwof the signal contacts .from one polar position totheother. impropenandundesiredoperation of the signals to. the; rear.upon a. change from yellow; to .green, for example, of a signalahead.

With HD relays constructed as described above, and as.diagrammatically;illustrated in connection.,with;relay MHD, forvexample,- no repeater relayis requiredi in connection, with. the type SAsignal. This is, because this type of relay retains its neutralcontactszclosed;not:only1while the relay is deenergized between currentimpulses but while the energization of. the relay is pole changedandatthe. same time is quick to pickup Let us assume that signal SM isdisplaying Hence, with a Thiszyellow-green; repeater prevents a cautionindication and that signal S18 which is next in advance thereof, isdisplaying a stop indication due to occupancy of the tracksection at theentrance to which signal Sl8 is placed. The signal next to the rear ofsignal SM, that is, signal Sl2,'wil1 of course be displaying a proceedindication. Assume now thatthe train advances so as to cause signal SIBto. change from stop to caution and that signal SM changes from cautionto clear. Signal Sl2, already at clear, should not change, but when thecontrol relay MI-ID for signal SM swings its polar contacts from oneside to the other to change the signal from caution to clear, if theneutral armature should release even momentarily, the polarity ofenergization on the control relay for signal SIZ would momentarilychange, and its green clear indication would change to yellow, orcaution, and then back to green. This change in the control relay forsignal S12 would cause a momentary change in the signal from green toyellow and back again of the signal next in the rear of it, and likewisethroughout the entire stretch of track.

The operation of the system shown in Fig. 3 should be clear from thedrawing without more detailed explanation than that given above,although it might be mentioned that the usual directional stick relaysare employed for the tumble-down circuits, such as the stick relayshaving the contacts IBS, MS, etc. Thus, if an east bound train entersthe stretch of track all of the west bound signals such as Sl3, SIT,etc., will go to stop, since the controlling stick relays, such as 138,etc., will not have picked up with this direction of trafiic. The stickrelays for the other direction, that is, Ms, I88, etc, will have pickedup, however. It further might be noted that the energy for picking uprelay MHD is indicated by and at the right-hand side of the figure ofdrawing while that for relay ill-ID is at the left-hand side of thedrawing.

From the above disclosure it can be realized that a retained neutralpolar relay is provided which is simple in construction and dependablein operation, and which can be made as slow to release as is desiredwithout interfering with its quick pick-up characteristic, and whichretains its neutral armature in energized position not only during shortoff periods of current, but also when the polarity of energization ofthe relay is changed.

The above rather specific description of one form of the presentinvention is given solely by way of example and is not intended in anymanner whatsoever in a limiting sense. It is to be understood thatvarious modifications, adaptations and alterations may be applied tomeet the requirements of practice without in any manner departing fromthe spirit or scope of the invention, except as limited by the scope ofthe appended claims.

Having described our invention, we now claim:

1. In a polar retained neutral relay, in combination, a main core, aretaining core spaced from the main core, a main winding on the maincore, a retaining winding on the retaining core, a movable polarizedarmature magnetically associated with the main core, a movable neutralarmature associated with both the main core and the retaining core, afull wave rectifier, circuit means conductively connecting the inputside of the rectifier across the main winding and the output side of therectifier across the retaining winding, and means for connectingelectrical energy of either polarity across the main winding forenergizing the said two windings in multiple.

2. In a polar retained neutral relay, in combination, a main core, aretaining core spaced from the main core, a main winding on the maincore, a retaining winding on the retaining core, a movable polarizedarmature magnetically associated with the main core, a movable neutralarmature associated with both the main core and theretaining core, afull wave rectifier, circuit means conductively connecting the inputside of the rectifier across the main winding and the output side of therectifier across the retaining winding, means for connecting electricalenergy of either polarity across the main winding, and means associatedwith the retaining core for op posing fiux changes in the retainingcore.

3. In a polar retained neutral relay, in combination, a main core, aretaining core spaced from the main core, a main winding on the maincore, a retaining winding on the retaining core, a movable polarizedarmature magnetically associated with the main core, a movable neutralarmature associated with both the main core and the re,- taining core, afull wave rectifier, circuit means conductively connecting the inputside of the rectifier across the main winding and the output side of therectifier across the retaining winding, means for connecting electricalenergy of either polarity across the main winding, and a low resistancewinding on the retaining core for opposing flux changes in this core.

4. In a polar retained neutral relay, in combination, a main core, aretaining core spaced from the main core, a main winding on the maincore, a retaining winding on the retaining core, a movable polarizedarmature magnetically associated with the main core, a movable neutralarmature associated with both the main core and the retaining core, afull wave rectifier, circuit means conductively connecting the inputside of the rectifier across the main winding and the output side of therectifier across the retaining winding, means for connecting electricalenergy of either polarity across the main winding, and a copper sleeveon the retaining core for opposing flux changes in the core wherebycurrent induced in the main winding can fiow in series, through the mainand retaining winding.

5. In a polar retained neutral relay, in combination, a main core, aretaining core spaced from the main core, a main winding on the maincore, a retaining winding on the retaining core, a movable polarizedarmature magnetically associated with the main core, a movable neutralarmature associated with both the main core and the retaining core,circuit means conductively connecting the two windings in series, meansfor connecting energy of either polarity across the main winding, andmeans in said circuit means for maintaining fiow of current through theretaining winding always in the same direction, regardless of thepolarity of the energy applied to the main winding.

6. In a polar retained neutral relay, in combination, a main core, aretaining core spaced from the main core, a main winding on the maincore,-

a retaining winding on the retaining core, a movable polarized armaturemagnetically associated with the main core, a movable neutral armatureassociated with both the main core and the retaining core, circuit meansconductively connecting the two windings in series, means for connectingthe two windings, in multiple, across in: said circuit-means formaintaining flow of current through the retaining winding in the samedirection, regardless of the polarity of the energy applied.

7. In combination with a two wire polarized line circuit, a' polarretained neutral relay including a main core, a retaining core spacedfrom the main core, a main winding on the main core, a retaining windingon the retainingcore, a movable polarized armature magneticallyassociated with the main core, a movable neutral armature:

associated with both the main core and the re taining core, a full waverectifier, circuit meansconductively connecting the input side of therectifier across the main winding and the output side of the rectifieracross the retaining winding, and means for connecting the line circuitacross the main winding.

8. In combination with a two wire polarized line circuit, a polarretained neutral relay including a main core, a retaining core spacedfrom the main core, a main Winding on the main core, a retaining windingon the retaining core, a movable polarized armature magneticallyassociated energy of either polarity; and asymmetric means with the maincore, a movable neutral armature associated with both the main core andthe retaining core, a full wave rectifier, circuit means conductiivelyconnecting" the input side of the rectifier across the main winding andthe output side of the: rectifier across the retaining winding,v meansfor connecting the line circuit across the main winding, and meansassociated with the retaining' core for opposing flux changes in theretaining core.

9. Ina retained neutral relay, in combination, a main core, a retainingcore spaced from the main core, a main Winding on the main core, aretaining winding on the retaining core, a movable neutral armatureassociated. with both the main core and the retaining. core, a full Waverectifier, circuit means conductively connecting the input side of therectifier across the main Winding and the output side of the rectifieracross the retaining Winding, and means for connecting electrical energyof either polarity across the main winding for energizing the said twowindings in multiple.

ROBERT J. LITTLE. THOMAS J. JUDGE.

